In current practice, quantitative filtration is usually accomplished by a lab technician using glassware items, tubing, a vacuum pump, tweezers, a ring stand, a pipette, petri dishes, and disposable pipette tips. The generally accepted procedure is as follows: with a special flat-bladed tweezer, a filter is carefully removed from between its protective sheets. With a special rolling motion, the filter is laid across a fritted glass filter stoppered into an Erylenmeyer side-arm vacuum glass. A cylinder with a flared, ground-glass base is carefully set over the filter and centered. A spring loaded clamp is then squeezed over the fritted glass and flared base of the cylinder to rigidly hold the system together. A sample of oil is taken using a pipette technique and squirted into the cylinder. Vacuum is applied and the progress of the filtration is monitored visually by the technician. Disassembly requires removal of the spring clamp, followed by carefully lifting the filter and placing it in an individual petri dish. Clean up requires a wash bottle and a waste container and sink.
Some attempts have been made to automate the foregoing processes. See for example, Nuxhall U.S. Pat. No. 4,020,676. However, Nuxhall represents a fairly complicated apparatus and does not provide a simple measuring means or an in-process holding tank to collect and hold unwanted fluids. Nuxhall also does not have a cover to prevent fluid introduction at inappropriate times. The need still exists for a simple system designed to minimize operator error and to simplify obtaining the desired quantity of fluid to be filtered.